create new class of Thumb in order to be better in Touch environment

MahApps.Metro/Controls/MetroTouchThumb.cs

@@ -0,0 +1,53 @@
+using System.Windows.Controls.Primitives;
+using System.Windows.Input;
+
+namespace MahApps.Metro.Controls
+{
+    public class MetroTouchThumb : Thumb
+    {
+        private TouchDevice _currentDevice = null;
+
+        protected override void OnPreviewTouchDown(TouchEventArgs e)
+        {
+            // Release any previous capture
+            ReleaseCurrentDevice();
+            // Capture the new touch
+            CaptureCurrentDevice(e);
+        }
+
+        protected override void OnPreviewTouchUp(TouchEventArgs e)
+        {
+            ReleaseCurrentDevice();
+        }
+
+        protected override void OnLostTouchCapture(TouchEventArgs e)
+        {
+            // Only re-capture if the reference is not null
+            // This way we avoid re-capturing after calling ReleaseCurrentDevice()
+            if (_currentDevice != null)
+            {
+                CaptureCurrentDevice(e);
+            }
+        }
+
+        private void ReleaseCurrentDevice()
+        {
+            if (_currentDevice != null)
+            {
+                // Set the reference to null so that we don't re-capture in the OnLostTouchCapture() method
+                var temp = _currentDevice;
+                _currentDevice = null;
+                ReleaseTouchCapture(temp);
+            }
+        }
+
+        private void CaptureCurrentDevice(TouchEventArgs e)
+        {
+            bool gotTouch = CaptureTouch(e.TouchDevice);
+            if (gotTouch)
+            {
+                _currentDevice = e.TouchDevice;
+            }
+        }
+    }
+}

MahApps.Metro/MahApps.Metro.NET45.csproj

@@ -162,6 +162,7 @@
     <Compile Include="Controls\MetroProgressBar.cs" />
     <Compile Include="Controls\MetroTabControl.cs" />
     <Compile Include="Controls\MetroTabItem.cs" />
+    <Compile Include="Controls\MetroTouchThumb.cs" />
     <Compile Include="Controls\MetroWindowHelpers.cs" />
     <Compile Include="Controls\MultiFrameImage.cs" />
     <Compile Include="Controls\NumericUpDown.cs" />
@@ -721,4 +722,4 @@
   </Target>
   -->
   <Target Name="AfterCompile" />
-</Project>
+</Project>

MahApps.Metro/MahApps.Metro.csproj

@@ -127,6 +127,7 @@
     <Compile Include="Controls\MetroProgressBar.cs" />
     <Compile Include="Controls\MetroTabControl.cs" />
     <Compile Include="Controls\MetroTabItem.cs" />
+    <Compile Include="Controls\MetroTouchThumb.cs" />
     <Compile Include="Controls\MetroWindowHelpers.cs" />
     <Compile Include="Controls\MultiFrameImage.cs" />
     <Compile Include="Controls\NumericUpDown.cs" />

MahApps.Metro/Styles/Controls.Slider.xaml

@@ -1,6 +1,7 @@
 <ResourceDictionary xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
                     xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
-                    xmlns:System="clr-namespace:System;assembly=mscorlib">
+                    xmlns:System="clr-namespace:System;assembly=mscorlib"
+                    xmlns:controls="clr-namespace:MahApps.Metro.Controls">
 
     <System:Double x:Key="HorizontalThumbHeight">16</System:Double>
     <System:Double x:Key="HorizontalThumbWidth">10</System:Double>
@@ -185,11 +186,11 @@
                                       Style="{StaticResource HorizontalTrackLargeDecrease}" />
                     </Track.IncreaseRepeatButton>
                     <Track.Thumb>
-                        <Thumb x:Name="HorizontalThumb"
-                               Height="{DynamicResource HorizontalThumbHeight}"
-                               IsTabStop="True"
-                               Width="{DynamicResource HorizontalThumbWidth}"
-                               Style="{StaticResource HorizontalSliderThumb}" />
+                        <controls:MetroTouchThumb x:Name="HorizontalThumb"
+                                                  Height="{DynamicResource HorizontalThumbHeight}"
+                                                  IsTabStop="True"
+                                                  Width="{DynamicResource HorizontalThumbWidth}"
+                                                  Style="{StaticResource HorizontalSliderThumb}" />
                     </Track.Thumb>
                 </Track>
             </Grid>
@@ -396,11 +397,11 @@
                                       Style="{StaticResource VerticalTrackLargeDecrease}" />
                     </Track.IncreaseRepeatButton>
                     <Track.Thumb>
-                        <Thumb x:Name="VerticalThumb"
-                               Width="{DynamicResource VerticalThumbWidth}"
-                               IsTabStop="True"
-                               Height="{DynamicResource VerticalThumbHeight}"
-                               Style="{StaticResource VerticalSliderThumb}" />
+                        <controls:MetroTouchThumb x:Name="VerticalThumb"
+                                                  Width="{DynamicResource VerticalThumbWidth}"
+                                                  IsTabStop="True"
+                                                  Height="{DynamicResource VerticalThumbHeight}"
+                                                  Style="{StaticResource VerticalSliderThumb}" />
                     </Track.Thumb>
                 </Track>
             </Grid>